Al-Kāfi - The Book of Commerce

Al-Kāfi - The Book of Commerce Chapter: Rule about Unlawful Interest ِنْ أَصْحَابِنَا عَنْ أَحْ٠َّدٍ عَنِ ابْنِ فَضَّالٍ عَنِ ابْنِ بُكَيْرٍ عَنْ عُبَيْدِ بْنِ زُرَارَةَ قَالَ سَ٠ِعْتُ أَبَا عَبْدِ اللهِ (عَلَيْهِ السَّلا٠) يَقُولُ لا يَكُونُ الرِّبَا إِلا فِي٠َا يُكَالُ أَوْ يُوزَنُ. 10.

A number of our people have narrated from Ahmad ibn Muhammad from ibn Faddal from ibn Bukayr from ‘Ubayd ibn Zurarah who has said the following: “I once heard abu ‘Abd Allah (a.s.), saying, ‘Riba’ comes in existence only in what is measured or is weighed.” وثق كالصحيح - Allamah Baqir al-Majlisi (Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (9/126))